The Malco FDS1 Flexible Duct Support eliminates air flow restrictions and increases efficiency to dramatically reduce utility bills and improve heated or air-conditioned room comfort. A properly supported 90° duct elbow typically improves air flow efficiency 10 to 40%. A Malco Duct Support quickly installs on new or existing flexible duct. The versatile FDS1 design uses either 36 or 48 inch nylon cable/zip ties to accommodate 4 inch to 16 inch diameters of flexible fiberglass wool duct as well as un-insulated flexible duct. And the strong, but lightweight, 100% recycled polymer support will not weigh down ducting.